In various kinds of display devices, optical elements, semiconductor elements, building materials, automobile components, nanoimprint techniques and solar cell members, deposition of liquid droplets on a surface of a substrate may cause a problem of contamination and corrosion of the substrate, or further the deterioration in the performance due to the contamination and corrosion. Therefore, in these fields, the substrate surface is required to have good water repellency.
As such films, Patent Documents 1 and 2 propose a surface-treated layer formed using a surface treatment agent such as (CH3)3SiO(Si(CH3)2O)46Si(CH3)2(CH2)2Si(OCH3)3.